The field of the disclosure relates generally to propulsion methodologies, and more specifically, to methods and systems for beam powered propulsion.
Most modern spacecraft or aircraft rely on chemical propulsion, for example, burning fuel and oxidizer to produce both energy and reaction mass. Various engine designs are used to convert this energy and reaction mass into thrust. Performance of these propulsion schemes is limited by the energy of chemical reactions and by the molecular mass of the reaction products, for example, water and carbon dioxide.
Alternative approaches have been examined. At least some of these alternative approaches use an external energy source, such as a beam of electromagnetic energy. By eliminating the need for combustion, the propellant can then be chosen to have low molecular mass, and therefore high exhaust speed for a given temperature. Since engine materials are limited by the peak temperature at which they can operate, this beamed energy approach allows higher exhaust speed (and therefore higher specific impulse) than chemical propulsion.
In one beamed energy solution, sometimes referred to as a windowed heat exchanger, the beam of electromagnetic energy (typically a laser beam) passes through a window on the side of a rocket or jet engine to reach a heat exchanger inside the engine. The window both confines a high pressure and handles a large temperature gradient. However, a window that performs both functions must be thick and therefore heavy, and such a window is typically made of exotic and costly materials.